Apparatus for recovering alkali.



G. F. LOGAN.

APPARATUS FOR REGOVERING ALKALI.

APPLICATION FILED MAR.13, 1908.

910,074. Patented Jan.19.1909.

4 SHEETSSHEET 1. 4

Sn-ventoz C. F. LOGAN.

APPARATUS FOR RECOVERING ALKALI.

APPLICATION FILED MAR. 18, 1908. 910,074, Patented Jan. 19. 1909. 4 SHBETS-SHBET 2.

gnvcnt Wihicooq f J. mom:

C. F. LOGAN.

APPARATUS FOR REUOVERIN G ALKALI.

APPLICATION FILED MAR.13, 1908.

074 Patented Jan. 19, 1909. 4 SHEETS-811F111 3.

/ Z6 Z7 4.4V

, fitter/Hugo G. F. LOGAN.

APPARATUS FOR REOOVBRING ALKALI.

APPLICATION FILED MAR. 18, 1908.

910,074. Patented Jan. 19,1909

4 SHEETS-SHEET 4.

U STATES ATENT APPARATUS FOR RECOVERING- ALKALI.

Specification of Letters Patent.

Patented Jan. 19, 1909.

Application filed March 13, 1908. Serial No. 420,886.

To all whom it may concem:

Be it known that I, CYRUS F. LOGAN, a citizen of the United States, residing at Big Island, in the county of Bedford and State of Virginia, have invented a new and useful Apparatus forRecovering Alkali, of which the following is a specification.

This invention has reference to improvements in the recovering of alkalies from solutions of the same, and is more particularly directed to the recovery of soda or other caustic alkalies from the refuse liquors of pulp mills, although also applicable to the recovery of other refractory chemicals from solutions.

It has been proposed to recover the alkali from the refuse liquors of pulp mills by permitting such liquors to flow down a suitable stack through which there is an ascending stream of hot products of combustion causing a partial evaporation of the liquid holding the alkali in solution. Ultimately, the partially concentrated liquor reaches a receptacle at the bottom of the stack where it is agitated and may in part be again ele-' vated toward the upper end of the stack and permitted to again flow to the bottom thereof. The more concentrated parts of the fluid within the receptacle are permitted to flow off into a rotary calcining chamher into which hot products of combustion are directed from a suitable source to complete the evaporation of the liquid and finally set fire to the dried mass reducing the same to ash, which ultimately escapes from the end of the calcining chamber remote from the stack, and from this ash the caustic soda or other alkali is recovered by leaching and any loss may be made up by fresh solution.

The present invention comprises certain improvements in apparatus of this character and is intended to remedy certain defects and avoid certain objections to apparatus heretofore used for a like purpose.

The invention comprises a stack, the inner Walls of which progressively diverge toward the upper or discharge nd so that the added volume of steam due to the evaporation of the water holding the soda and other soluble materials in solution will not cause an acceleration of the flow of the products of combustion up through the stack. Therefore, the upflow of hot gases act for a lon er time upon the downtlowing stream of so ution than is the case with a stack of the them to pass through thin streams of the.

liquor.

Furthermore, provision is made in accordance with the present invention for preventing the escape of any particles which it is desirable to retain, and the top of the stack is provided with a cover protecting the stack from the entrance of rain which would tend to dilute the liquor being treated.

It is furthermore the purpose of the invention to provide means at the base of the stack for the reception of the'partially concentrated liquor flowing down the stack and such receptacle or tank is provided with means for agitatin the concentrated liquor and finally elevating it to a point from which it may be led into the neck of a r0- tary calcining chamber.

It is a further object of the invention to so construct the neck of the calcining chamber that the inflowing liquor is spread in a.

thin layer thereon and so additionally subjected to the evaporating efi'ects of the products of combustion.

In connection with the calcining chamber there is used a fire chamber or furnace which may be adapted to burn any desired kind of fuel but which may be moved into or out of operation to the discharge end of the calcining chamber.

It is also the urpose of the present invention to provide the base of the stack above the concentrating tank with a number of openings so that a number of calcining chambers may be employed at the same time, or a single calcining chamber may be used and furnaces may be applied to the other openin s in the stack. These openings are normally closed by suitable doors when not in use.

By reason of the large evaporating surface provided for the downfiowing liquor in the stack and the retardation'of the esca ing products of combustion and also t e presentation of a large evaporating surface at the neck of the calcining chamber, the

concentrate, when it reaches the interior of I lire by the burning of the material closer to the discharge end of the said calcining chamber. Therefore, after the furnace has been used long enough to start the operation of the device the furnace fire may be allowed to die out and the incineration of the material within the calciningor incinerating chamber continues automatically saving in the cost of the recovery ofthe alkaline materials.

In accordance with the present invention provision is also made'whereby the concentrated liquid elevated from the top of the receiving or concentrating tank may be directed into the calcining chamber or may be caused to flow back into the tank in case it is found that too much liquid is being directed into the saidcalcining or incinerating chamber.

The invention will be best-understood by a consideration of the following detail description taken in connection with the accompanying drawings forming a part of this specification, in which draw-in s Figure l is a side elevation, partly in section, of an apparatus built in accordance with the present invention. Fig. 2 is a horizontal section on a plane through the axis of the incinerating chamber. Fig. 3 is a vertical section on a plane through the axis of the incinerating chamber. Fig. i is a vertical section on the line A-B of Fig. 3,

with parts broken away. Fig. 5 is a horizontal section similar to that of Fig. 2, to show the use of a number of mcinerating chambers with one stack. F 1g. 6 1s a cross section on the line *C-l) of Fig. 4-. Fig. 7 isa cross section showing a modified form of conduit from the elevator to theneck of the lncineratlng chamber.

-Referring to the drawings, there is shown a stack or chimney l of suitable height for the purposes of the invention, and the interior wall of the chimney is made gradually divergent from the lower end to the upper end. lhe inner face of the chimney may be made of vitrified brick or other suitable material, while the rest of the body of the chimney may be made of other material of a cheaper nature since it does not have to stand the action of the caustic materials and the heat. Since it is designed to provide access to the base of the chimney from several points, the chimney may be built upon steel trusses 2 supported by suitable trussed pillars 3, and these pillars in turn rest upon a solid base or foundation 4. At the foot of the chimney there is formed an inwardly-directed ledge 5 all about the interior of the chimney, and this ledge, like the interior face of the chimney, is made of vitrified brick or similar material.

Resting upon the base 4 below the chim- The tank extends between two of the columns 3 and beyond the same, as shown at 9, and there isformed at one end a pocket or depression 10'. Extending longitudinally through the semi-cylindrical bottom portion of the tank 6 is a horizontal shaft 11. suitably journaled in the walls of the tank, and this shaft carries blades 12 so shaped as to agitate any fluid which may be in the tank and cause the same to move in a direction toward the pocket 10. The purpose of this agitator and conveyer will appear further on. The extended portion 9 of the tank is surrounded by suitable walls 13 carried upward to a point approximating the base of the stack, and near the top of the wall 13 is journaled one end of a shaft- 14: one end extending outside of the wall 13 while the other end of the shaft has its journal bearings supported on the body of the stack. The shaft 12 extends through suitable stuffing box to the exterior of the tank, where it has secured to it a sprocketwheel 15, and. upon the shaft 14: exterior to the wall 13 is another sprocket wheel 16, and these two sprocket wheels are coupled by a sprocket-chain 17. Journaled in the bottom of the tank over the depression 10 is another shaft 18 upon which is carried a sprocket wheel or pulley 19, and the shaft i l also carries inter or to "the wall 13, another sprocketwheel 20. vThe wheels 19 and 20 receive achain 21 carrying a number of buckets 22, the said buckets being so disposed as to enter the depression 10 to elevate any material which may be therein'to a point above the top of the tank 6. In the path of any material which may be carried by the buckets 22 as they discharge is a deflector 23 mounted upon suitable brackets 24 fast to the inner face of th%'-Wal.l' 13- This deflector may be tilted to direct material deposited thereonin one wayor another as desired, for a purpose which will hereinafter appear. Adjacent to the base. 4'

tial rails 29 upon a rotary incinerating tank 30 which may be made of a suitable metal frame 31 with an inner lining of refractory material 32, such for instance as fire brick.

The incinerating chamber 30 is provided with an elongated axial neck 33 at one end, which neck has formed at its free end an inwardly-directed radial lip 34. The neck may be suitably braced by brackets 35. The mouth of the neck 33 is designed to enter between two of the columns 3 so as to be closely adjacent to the corresponding side wall of the tank 6, and during the operation of the device the. chamber 30 is to be ro= tated upon a horizontal longitudinal axis, as will hereinafter appear. The end of the chamber 3Q 'emote from the neck 33 is provided with an axial opening 36, and into coincidence with this opening there may be brought the discharge end 37 of a suitable furnace 38, mounted upon a continuation 39 of the framework 25, the said framework 25 being supported at this end of the structure upon a pillar 40 resting upon a separate base 41. The opening 36 and the furnace discharge end 37 are so related that there is provided an exit 42 for the incinerating -'chamber so that material in said chamber may pass out through the exit 42 and drop upon a convey-er 43 mounted in a trough 44, the said conveyer being provided for the purpose of transporting material dischar ed from the incinerating chamber to a suita le distance for further treatment.

Adjacent to the deflector 23 is a receptacle 45, from which extends a pipe 46 having its free end 47 entering the neck 33 interior to the lip 34 in such manner as to direct any material flowin through the pipe 46 into the neck towar "the incinerating chamber. The pipe 46 is slightly inclined as a whole from the receiving end to the discharge end. This pipe may be made of iron with an ex-' terior coating of refractory material such as fire brick ,or the like, and this protecting coating should be slightly separated from the iron ipe to allow for expansion.

Referrlng again to the stack 1, the upper endof this stack is surrounded by a trough or gutter 48, the inner edge of which is cartied up over the edge of the stack and then turne downward coincident with the face of the interior of the stack. The outer walls 49 of the-tron h 48 are continued upward concentric wit the axis-ofthe stack and are ultimately turned inward, as shown at 50, to receive a ring 51 supporting a cylindrical screen '52 which in turn is cap ed by a conical top 53, which latter is mad solid for the purpose of preventing the entrance of rain or other matter into the stack. To further protect the exit end of the stack the cap 53 is extended beyond theouter edge of the screen 52, as shown at 54, and there provided with a gutter 55 from which may lead a down spout 56 to any suitable point of discharge. By this meansany gases passing upward through the stack find ready escape through the screen 52, while rain or snowor other products of weather conditions are prevented from entering the stack. Also the screen will throw back into the stack valuable materials which might otherwise be discharged from the stack and so be lost.

Immediately above the upper end of the bod of the stack are a number of conical bafli es 57, 58, 59. While but three of these battles are shown in the drawings it will'be understood that the number may be increased or decreased as conditions may warrant. The lowermost baflle 57 has a greater spread than the mouth of the body of the stack so that its lower edge overhangs the trough 48 and the baffle is provided with a central opening 60. The baflle 58 is of less diameter than the baille '57 and is likewise provided with an opening 61 immediately above the opening of the baflle 57 The bafile 59 is of smaller diameter than the baiile 58 and is closed at the top to form a crown over the open end of the baffle 57. Above'the crown bafiie 59 is the discharge end 62 of a pipe 63 entering throu h the screen 52 and extending downward a ongside of the stack, as shown, to a pump 64 mounted upon a suitable support 65 adjacent to the foundation 4. This pump is driven by a suitable shaft 66 receiving power through a pulley 67 from. any source of ower that may be desired. Leading from t e pump 64 is a pipe68 entering the tank 6. At an appropriate point is a supply tank 60 connected by a pipe 70 to the tank 6 near the upper end thereof, the supply tank 69 being on a level with, or if desired, slightly elevated above, the tank 6. Within the tank 6 is a float 71 connected through links 72-73 to the handle of a valve 74 controlling a steam pump 75, the arrangement being such that the valve 74 will be opened by the falling of the, float when the material within the tank 6 drops below a certain level, and when the level is again restored the valve 74 will/be closed automatically. Of course, an electric motor and switch may be used in place of a steam pum and valve, or any other motor may be emp oyed.

The entire structure except the stack is ,inclosed by a suitable building. The stack approximately 1000 pounds of cellulose and about 2800 pounds more or less of refuse passes off with the caustic soda solution. In order to recover the soda, it is necessary to treat a large quantity of material, and heretofore with structures built. for the purpose it has been necessary to use largequantities of fuel since the incineration of the loaded soda solution was only possible close to the source of heat, and consequently the initial supply of heat had to be constantly maintained. Vith the structure described herein the loaded or waste soda solution receives such treatment that it becomes thoroughly dried and may be inflamed, and then the heat due to the incineration process will be found sufiicient to progressively dry and set on fire the material more rapidly than has heretofore been possible, even when sources of heat have been maintained continuously.

Let it be assumed that the tank 6 is filled with the loaded or waste soda solution and that there is a supply maintained in the tank 69 from the pulp mill. Let it also be assumed that there is a fire of suitable proportions in the furnace 38, it being understood that the furnace may be replacedv by any other suitable source of heat, the particularsource of initial heat supply not constituting a part of the present invention. The pump (a is also assumed to be in operation so that the soda solution is pumped from the discharge end 62 of the pipe 63 upon the baffle or spreader 59 and falls in a thin stream over the outer edge of this battle onto the next bafile 58 to again fall in a thin stream upon the baffle 57 and be finally directed ina thin stream into the gutter 48. When the latter structure, namely the gutter 48, is filled, the soda solution overflows the inner edges of the latter and passes down in a thin stream all about the inner wall of the stack 1, which inner wall, it is to be observed, continuously tapers toward the lower end of the stack. Ultimately, the material reaches the ledge 5 and passes of]? the edge of the same also in a thin stream into the tank 6.

While the loaded soda solution is flowing downward it is subjected to the hot products of combustion coming from the furnace 38, these hot products in their hottest state first meeting the stream falling from the ledge 5 and then acting on the flowing streams along the inner wall of the stack 1. Part of the water holding the soda and other materials in solution or suspension is converted into steam or vapor as the hot products of combustion move upwardly, but since the cross sectional area of the stack is continuously increasing the upward flow of the products of combustion and vapor carried thereby is not correspondingly accelerated because of the added volume due to the evaporated water, and so the downflowing stream of soda solution is subjected for a longer time to the evaporating and heating eflect of the prodnets of combustion than though the stack was of the same cross sectional area throughout or for a large portion of its length.'

lVhen the products of combustion reach the baflle plate 57 they are diverted in part around the lower edges of the same and pass through the downflowing stream of solution dropping from said edges. A portion of the products of combustion pass through the opening 60 and into the bafile plate 58, and such products of combustion are in part diverted around the lower edge of the said baflle plate passing through the downflowing stream of the solution. F inally, such of the products of combustion as pass through the opening 61 escape under the edge of the bafiie 59, and ultimately all the products of combustion with the steam or vapor carried thereby find their way out through the screen 52. The result of this is that the soda solution has been continuously heated and largely evaporated before it again reaches the tank 6.

In the continuous process the soda solution in the tank 6 becomes much thickened or con cent-rated and the concentrated solution gravitates to the bottom of the tank to be there agitated and fed toward the depression 10', whence the solution is elevated by the buckets 22 until the latter discharge into the deflector plate 23, which maybe so tilted as to cause the concentrated solution to fall into the receptacle 45 and be directed into the conduit 46, along which the heavy solution flows to the outlet 47 and ultimately drops into the'ncck 33. It will be understood of course that the elevator buckets and the agitator inthe bottom of the trough may be kept in motion by power suitably applied to the shaft 14:. By the time the solution has reached the neck 83 it is in a thick syrupy or pitch-like condition, and because of the rotation of the chamber 30, which itis understood is continuously rotated, the solution spreads out in a thin layer over a considerable area of its neck before it ultimatel gravitates into the chamber 30. All the time the evaporation continues until by the time the solution reaches the chamber 30 it is so far concentrated as to be in an inflammable condition and the combustible portions take-fire and burn out leaving the refractory soda ash within the chamber 30, and this ultimately escapes through the opening 42 onto the conveyer 48 progressively.

As soon as the process is well under way the burning of the inflammable material within the chamber 30 supplies all the heatnecessary for the carrying on of'the process and the fire in the furnace 28 may be permitted to die out, or if the fuel be a gaseous or oil fuel it may be turned ofi'.

As the level of the material in the tank 6' drops the float '71 will fall and the valve 74 will be open and fresh material from the tank or reservoir 69 will be pumped into the tank 6. From time to' time an inspection of the interior of the lower end of the stack and the chamber may be had by a suitable door 79 in the wall 13, and by means of suitable tools any parts which may become clogged or overchar ed may be cleaned. If itbe found that the lmr'ning limit in the incinerating chamber is retreating too near .the discharge end of the latter then the inflow of concentrated material by. way of the trough 45 may be temporarily arrested by throwing the deflector plate 23 in a direction to return the elevated material into the tank 6, and when the proper burning limit is again reached the material may be once more directed into the conduit 46 and discharged into the neck 38.

The foregoing description has been largely confinedto the use of the structure for the recovery of caustic soda from the refuse liquor of pulp mills. 'Of course the apparatusis also applicable for'the recovery of other refractory materials, and consequently is not limited to use with caustic soda only.

It is sometimes desirable to increase the capacity of the apparatus, and in such case a greater amount of the liquor may be concentrated by supplying more heat to the stack than is supplied by a single incinerating chamber. Fpr this purpose the base of the stack may be built with openings 79 on each side thereof at-right angles to the open* ing into which the neck of the incinerating chamber enters,- and these openings are normally covered by doors 80 moving in guides 81 and actuated by chains 82 each passing over a pulley 83 on the side of the stack and leading to some suitable point. -When the doors 80, which of" course are made of or lined with refractorymaterial, are opened, then furnaces like the furnace 38 may be applied to these openings and additional heat be furnished. The same structure is adapted for the use of additional incinerating chambers -30 so that the capacity of the apparatus may be very materially increased by using a number of incinerating chambers with a single stack, thereby largely increasing the outow of hot gases and effecting a correspondingly more rapid evaporation of the liquid in the solution. Under these conditions a single tank 6 may be utilized and the receptacle 45 will likewise be provided with, an additional number of conduits 46, leading each to the neck 33 of a respective incinerating chamber.

Instead of the receptacle 45 and direct conduit 46, a trough-like conduit 84 (see Fig. 7) underlying'the ledge 5 and protected by the same may be used. Such trough conduit is provided with an elongated neck 86, into which the deflector 23 may discharge, and a spout 87 is provided to enter the neck 33 of the incinerating chamber.

WVhat is claimed is 1. In a calcining apparatus, a concentrating chamber in the form of a stack having its walls progressively and continuously approaching from the upper end toward the lower end, and having its interior free or unobstructed, means for directing liquid to be concentrated against the inner walls of the stack at the upper end thereof, and a receptacle for the cencentrate. at the lower end of the stack.

2. In an incinerating apparatus, a concentrating chamber in the form of a. vertical stack having thecross-sectional area of its interior progressively and continuously lessening from the upper end toward the lower end, and having its interior free or unobstructed, means for directing liquidto be concentrated against the inner walls of the stack at the upper end thereof, and a receptacle for the concentrate at the lower end of the stack.

3. In an incinerat-ing furnace, a; concentrating chamber in the form of an upright stack, and means for directing a stream of,

liquid to be concentrated to the inner walls of said stack comprising a trough or gutter exterior to the upper end of the stack and ex-' tending below said upper end and having its inner edge coincident with the inner face of the stack, and a battle above the tron h or gutter for directing the stream of liqui into the said gutter.

4. In an incinerating furnace, a concentrating chamber in the form of a stack provided with a trough or gutter exterior to its upper edge and communicating with the interior of the stack over the upper edge, means for directing heated gases into the stack from lower end thereof, and means for directing a stream of liquid to be concentrated throu h the outflowing stream of heated gases to t gutter or trough surrounding the upper edge of the stack.

5. In a calcining apparatus, a concentrating means for the liquor to be treated comprising a stack, means for directing heated gases thereinto from one end, a trough or gutter surrounding the other end of the stack and leading thereinto over the said end of the stack, the said (gutter having'continuing walls beyond the en of the stack, a series of battles beyond the end of the stack in the line of travel of the heated gases, and a means for directing a stream of a solution to be concentrated upon the baffles.

6. In a calcining apparatus, a concentrating chamber comprisin battles at the exit thereo means for directing a stream of solution to be concentrated upon a stack, a series of the bafies, a trough or gutter exterior to the stack about the discharge end thereof and in the-path of the solution escapingirom the battles, and a screen forming the exit end of the stack beyond the bafiles.

7. In a calcining apparatus, a stack, bafies at the exit end thereof, means for directing a stream of the solution to be concentrated onto the baflies, a trough or gutter exterior to the stack in the path of the steam escaping from the baflles and overflowing into thestack, a screen beyond the bafiies and constituting the exit end of the stack, and a cover for the screen projecting beyond the same and provided with means for the disposition of rain or other weather depositions upon the discharge end of the stack.

8, In a calcining apparatus, -a concentrating chamber in the form of a stack having its interior cross sectional area constantly and progressively increasing toward the discharge end of the stack, a gutter about the upper end of the stack in position to overflow thereinto, the said gutter having its outer walls extending above the body of the stack,

a number of elongated plates of progressing area the longest of which has its lower ed es coincident with the gutter and each of which is provided with a central exit passage, another bafie surmounting the first named b'aihes and constituting a spreading baffle,

, means for directing a stream of-the solution to be concentrated upon the spreading bafie, a screen supported by the extended walls of the gutter and constitutin the-exit opening of thestack, and a cover For the screen tapping the same.

9. In a calcining apparatus, a concentrating chamber'in the form of a stack having its walls constantly and'progressively diverging from the lower end toward the upper end of the stack, a series of baflies at the upper end of the stack body, a gutter-surrounding the stack body and having one edge arranged coincident with the top of the body of the stack and the other edge in the form of an upwardly-continuing wall, a door in said lastnamed gutter wall, means for directing a stream of the solution to be, concentrated upon the bafiles to be ultimately discharged into the gutter, a screen surmounting the extended walls of the gutter, a protecting cap topping the screen, and means exterior to the stack for permittin access to the door in the extended gutter wa ls, r

10. lln a calcining apparatus, a concentration tank, a rotatable incinerating chamber having an elongated neck, and means for conveying the concentrate from the tank to the elongated neck of the incinerating chamber,

11. In a calcining apparatus, a rotatable incinerating chamber provided I with an elongated neck into which concentrate is deposited,

cinerating chamber compris' provided with means discharging into the eropva 12. In a calcining apparatus, a concentration tank, an incinerating chamber, means for elevating material from the bottom of the concentration tank, and means for conveying the elevated material to the incinerating chamber, s

13. in a calcining apparatus, .a rotatable incinerating chamber provided with an axially disposed elongated neck, a concentration tank, a conduit above the tank and dis 15, in a calcining apparatus, an incinerat- I ing chamber, a. stack communicating therewith, a concentration tank beneath the stack, and below the mouth of the incinerating chamber and means for directing material from the bottom of the concentration tank into the incinerating chamber, I J

16. ln a calcining apparatus, an incinerating chamber, a stack communicating therewith, a concentration tank beneath the stack, means for directing material from the bottom of the concentration tank into the incinerating chamber comprising a conduit betweenthe incinerating'chamber and stack.

and provided with means discharging into the incinerating chamber, and an elevator in operative relation to the bottom of the concentration tank and with the conduit,

17. In a calcining apparatus, an incinerating' chamber, a stack communicating therewith, a concentration tank beneath the stack, means for directing material from the bottom of the concentration tank into the ina conduit incinerating chamber, an elevator in operativerelation to the bottom of the concentration tank and with the conduit, and means operative relation to the discharge end of the elevator for directing material elevated thereby into the conduit or back into the tank. I v x 18. in a calcining apparatus, annincinerat ing chamber provided with an elongated neck at the exit end, a concentrating tank, means for causing the dis harge of concentrated material from said tank intothe neck of the incinerating chamber, and a stackin communication with the'incinerating chamber and concentration tank provided with means for retar the flow of products of combustion from t e .incinerat ing tank through the stack and with means treating the material between the concentrafor directing a stream of the material to be tion' tank and the incinerating chamber in treated into the path of such products of combu tion. 5 19. In a calcining apparatus, an incinerating chamber, a concentration tank, a stack in communication with the incineratin-g chamber and concentration tank, means for subjecting the material to be treated in thin 10 streams to the action of products of combustion within the stack, and means for thin streams to the action of the products of combustion.

In testimony that I claim the foregoing as my own, I have hereto aflixed my signa- 1 ture in the presence of two witnesses.

CYRUS F. LOGAN. Witnesses W. O. BELL, J. L. NIo oLAs. 

